During the performance of endoscopic or arthroscopic surgery, it is often necessary or useful to be able to perform a power assisted cutting, drilling, chipping, or other similar action on a variety of tissues. Such actions may be applied to muscle tissue, other soft tissue, or bone. The type of knife or other implement used for each function is specifically designed for the given type of action to be performed on a given type of tissue. Similarly, the motion which is imparted to the implement is designed to operate the specific implement in the preferred way. The mode of motion used in known power tools is either pure rotation or pure reciprocation.
For instance, the implement could be a drill, a scalpel, a burr, a rasp, a chisel, a rotary cutter, or a reciprocating cutter. The particular implement selected might perform better with a rotary action, or a reciprocating action. The preferred action might depend upon the type of tissue being operated on, as well as upon the type of implement. For the sake of simplicity, the action performed by these implements often will be referred to herein generally as "cutting", it being understood that for some implements, the action might more accurately be described as chiseling, filing, or some other action.
Such a known power tool would be an integral tool which might typically incorporate a handle such as a pistol grip, a drive mechanism, and a sheath through which the cutting implement is driven. The sheath might be open ended, or it might have an enclosed end, with the integral cutting implement being exposed through a side window. It is currently known to select a power tool which incorporates the desired type of cutting implement, with the power tool being designed to impart the selected mode of motion to the implement. Each currently known tool is limited to imparting either a rotary mode or a reciprocating mode of motion, to the cutting implement.
Such currently known power tools are typically electrically powered through a cable attached to the handle, or pneumatically powered through a hose. The electric motor and other elements of the drive mechanism are specifically designed to impart a rotary mode of motion to the cutting implement, or to impart a reciprocating mode of motion to the implement. When the surgeon wishes to switch to a different cutting implement, he must switch to a different power tool which incorporates the desired implement, and which is designed to impart the desired mode of motion to the implement.
There are several disadvantages to the currently known power surgery tools. First, the surgeon must switch to a different power tool if he wishes to use a different cutting implement. This requires that a relatively large number of power tools be made available for an operation, adding to clutter in the operating room, and adding to the expense of the surgery. Second, sterilization of a large number of power tools adds to the cost of the surgery and further taxes the resources of the hospital. Third, the hospital must insure that it has on hand a large number of power tools in order to meet the needs experienced during a wide variety of surgical operations. Fourth, currently known power tools are capable of imparting only rotary or reciprocating motion to a cutting implement. Many implements perform optimally when given a combination of rotary and reciprocating motion.
Therefore, it is an object of the present invention to provide a portable power surgery tool in which a portion of the drive mechanism can be changed to switch from one mode of motion to another mode. It is a further object of the present invention to provide a portable power surgery tool in which the cutting implement and a portion of the drive mechanism can be replaced as a disposable unit, to switch from one implement which requires a given mode of motion to another implement which requires a second mode of motion. It is a still further object of the present invention to provide a portable power surgery tool which is capable of imparting a combination of rotary and reciprocating motion to a cutting implement. It is yet a further object of the present invention to provide a portable power surgery tool which is economical to make and easy to use.